1. Field of the Invention
The present invention relates to system of using labels for multi-well plates useful in a variety of applications. More particularly, the invention relates to use of one or more labels to unambiguously identify the location of samples in a multi-well plate for proper orientation of the samples when loading samples into a plate and loading the plate into a device such as a processing center or plate reader.
2. Description of Relevant Art
Multi-well plates are typically used in high-throughput applications as well as in numerous research and development applications. Multi-well plates typically comprise an array of depressions formed in a generally planar surface of a tray and may be provided with a lid. Typical multi-well plates contain 96, 192, 384, or 1536 rectangular receptacles which must be filled with a predetermined amount of a liquid or other sample and later manipulated.
Certain multi-well plates are specifically adapted for growing cells in media. These multi-well plates have a multi-well plate which may be placed into a tray containing growth media. An example of this type of multi-well plate is an insert plate. In insert plates, the wells include a porous membrane toward the lower end of the well. The plate is placed in the tray. The membrane can contact the media in the tray and is permeable to various compounds such as nutrients and the like. Examples of insert plates include BD Falcon™ HTS FluoroBlok™ Insert Systems and BD Falcon™ HTS Insert Systemsavailable from Becton Dickinson and Company, Franklin Lakes, N.J.
Strip plates are one form of multi-well plates suitable for use in ELISA assays and PCR reactions. Strip plates are multi-well plates having a plurality of individual rows of wells arranged in a support member. The individual rows of wells are referred to as strips. A typical strip plate will include eight (8) or twelve (12) wells per strip. The support members are configured to fit into a frame. The frame is configured to hold eight (8) or twelve (12) such strips. It is possible to use one or more of the strips in the frame for any given procedure.
The use of multi-well plates depends upon the particular application. Multi-well plates are often used in high-throughput assays and other biological applications by testing batches of compounds also referred to as libraries or combinatorial libraries, for binding activity or biological activity against target molecules such as cells, an antibody, receptor, enzyme, transcription factor or the like.
To facilitate high-throughput screening techniques, a number of automated platforms have been developed. One system, for example, includes an automated multi-purpose analytical chemistry processing device and laboratory work station having a movable table for supporting multi-well plates and other fluid receptacles, a movable arm, and a modular mobile pod affixed for reciprocal movement along the arm.
The workstation combines into a single programmable system the capabilities for automation of a wide range of bioanalytical procedures including, not only sample pipetting, serial dilution, reagent additions, mixing, reaction timing and similar known manual procedures, but also programmable spectrophotometric measurements and other physical parameters, further processing based on these measurements and automatic data recording. Multi-well plates must be designed to conform to the specifications of such automated processing centers used in modern high-throughput assays.
Additionally, prior to the use of high-throughput assays, conditions must be optimized in order to make such assays reliably usable in such a platform. Multi-well plates are often therefore used in assay development applications. In these applications, as opposed to high-throughput applications, it is often necessary to manually fill the wells of the multi-well plates and then to manually load the filled plates into a device such as a plate reader.
Furthermore, academic research is often performed in a laboratory setting that is not equipped to perform high throughput assays. Rather, the research is performed as described above, with manual filling of multi-well plates and manual placement of the plates into plate readers or the like.
It is important while adding samples into the plates and loading them into a processing center or other device to be aware of the identity of the sample in each well. Multi-well plates are usually labeled in some fashion in order to allow a user to specifically identify each sample in each well. For example, plates having alphanumeric identifiers of well locations are known. These plates have an indication of horizontal sequential numbers along a perimeter of one side of the plate and an indication of vertical sequential letters along a perimeter of an adjacent side of the plate. Usually these indicators consist of raised alphanumeric indicators of the same color as the plate. It is possible to use these alphanumeric labels to properly orient the plates into devices such as plate readers and the like.
Additionally, some multi-well plates are also configured with a geometry at the base of the plate or tray so as to require they be placed in a particular orientation when being loaded into certain devices. In these configurations, there is no corresponding geometry in a plate accepting portion of the device to that of the base of the plate or tray. Consequently, the multi-well plates may be placed in the device in either orientation.
The Society for Biomolecular Screening (SBS) has set standards for microplates including standard SBS-1 Footprint Dimensions and standard SBS-4 Well Positions. Presently, there is no universally accepted standard for design of plates and devices such as processing centers and/or readers so that the plates can be loaded into the devices in only one orientation. For devices and multi-well plates which are not configured so that the plate may be placed in the device in only one orientation, it is possible to mis-load the plates into the device. Specifically, it is possible, such as, for example, when using a Victor 2 Multilabel Counter (Perkin Elmer Wallac Inc., Gaitherburg, Md.) or a Discovery-1™ High Content Screening System (Molecular Devices, Sunnyville, Calif.) to load the plates in more than one orientation.
Improper orientation of the plates in the device can result in either a loss of data or collection of data that is incorrect. A user loading the plates into the reader quickly may not notice whether the alphanumeric labels are in the proper orientation. This is especially true when the alphanumeric indicators are the same color as the plate. Furthermore, when multi-well plates are stacked, it is not possible to see the conventional multi-well alphanumeric markings on any but the topmost plate. A user who believes they have stacked a plurality of plates in a single orientation may later load a device with the plates using a technique in which the plates are each placed in the device in the same orientation in which they have been stacked. Inadvertent mis-stacking of the plates may not be detected at the time the plates are loaded into the device.
It is therefore desirable to have an unambiguous label and system of labeling to avoid the possibility of misloading plates into devices such as processing centers and/or readers.
Furthermore, it would be advantageous to have a label and labeling system in which the orientation of samples in a plurality of plates can be viewed when the plates are in a stacked configuration.